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利用RMT-150C型岩石力学伺服试验系统和CDAE-1型声发射检测仪,以余吾煤业3号煤层顶板不同层位的两组砂岩为研究对象,在单轴压缩条件下进行声发射实验。实验结果表明:A组砂岩达到峰值前的应力应变曲线近似于直线,达到峰值后直线迅速下降到零,B组砂岩的应力应变曲线先下凹再直线上升(斜率小于A组),达到峰值后,先保持一定承载力后才下降到零。初始压密阶段,两组岩样的声发射计数很少且能量很低;弹性阶段,A组砂岩的声发射事件略有增加,但能量、计数率和能率几乎为零,而B组砂岩的声发射事件逐渐开始活跃;塑性阶段,A组砂岩的声发射事件逐渐开始活跃,B组砂岩发生片帮,声发射参数跳跃式增大;峰后破坏阶段,达到应力峰值时,两组岩样的声发射计数、能量、计数率和能率都达到最大值,B组砂岩峰后还有一定地声发射事件发生。两组砂岩的声发射规律差异可为判断声发射源和监测预报何处岩石失稳破坏提供参考依据,对提前做好防护工作减少灾害发生和未来进一步研究具有一定意义。
Using the RMT-150C rock mechanics servo test system and the CDAE-1 acoustic emission detector, two groups of sandstones in different layers of roof of No. 3 coal seam of YuWu Coal Mine were studied. The acoustic emission experiment was carried out under uniaxial compression. The experimental results show that the stress-strain curve of sandstone in Group A is similar to the straight line before it reaches the peak value, and the straight line rapidly drops to zero after it reaches the peak value. The stress-strain curve of sandstone in Group B is concave and then linearly rising (slope is less than that in group A) , First maintain a certain bearing capacity before dropping to zero. In the initial compaction stage, the acoustic emission counts of the two groups of rock samples are very low and the energy is very low. During the elastic phase, the acoustic emission events of sandstone group A slightly increase, but the energy, counting rate and energy rate are almost zero, Acoustic emission events gradually began to be active. During the plastic phase, acoustic emission events of sandstone in Group A gradually began to be active. The sandstone in Group B occurred patchy and the acoustic emission parameters increased abruptly. After the peak failure phase, The acoustic emission count, energy, count rate and energy rate all reach the maximum value, and some acoustic emission events occur after Group B sandstone peak. The difference of acoustic emission law between the two sandstones can provide a reference for judging the acoustic emission sources and monitoring the rock instability and failure of the rock, which is of great significance to advance the protection work and reduce the occurrence of disasters and further study in the future.